a) Field of the Invention
The invention is directed to a device for horizontal and vertical adjustment in geodetic devices, especially in theodolites and tacheometers, which enables precise sighting adjustments, e.g., of the telescope of these devices.
In particular, this concerns the adjusting gear units for the sighting adjustment for the Hz (horizontal) and V (vertical) directions of the telescope of a tacheometer or theodolite.
b) Description of the Related Art
In older geodetic devices, simple mechanical gear units were provided, by means of which the corresponding movements were carried out for every adjusting direction (Hz or V), e.g., for rotation of the alidade about the vertical or standing axis and for rotation of the telescope about the tilt axis, by actuating a handle, usually in the form of a rotating knob. Generally, this involves a simple screw which is supported at a fixed fine adjustment lever and contained by a counterspring buffer, this fine adjustment lever being connected with the structural component part of the device to be moved. To simplify handling, the two movement directions of the two rotating axes (standing axis and tilt axis), which movement directions are at right angles to one another, were combined in a coaxial drive by means of a complicated mechanical lever gear unit. It was also necessary to clamp both movement directions (Jenaer Rundschau, Vol. 19 (1974), Issue 1, pages 13 to 15, Illustrations 1 and 2).
In leveling devices, a simple and quick, but imprecise, rotation about the standing axis was necessary in order to swivel the telescope quickly from one stadia setting to the next. For this purpose, the slip clutch was introduced for coarse adjustment and the worm gear, with worm, was introduced for fine adjustment. A prerequisite for this is that the tripod, with its foot screws, possesses a certain directional stability. This is of secondary importance for leveling. For theodolites, this influence is not negligible. For this reason and in view of the fact that sensitivity of the sighting adjustment can be realized only with difficulty, the system of the slip clutch with worm and worm gear was not previously widely used in theodolites (system in all compensator leveling).
By replacing the mechanical drive with motor control systems and sacrificing a certain quality of sighting adjustment, the slip clutch with worm gear and worm was also introduced in electronic tacheometers for rotation of the alidade about the standing axis and for rotation of the telescope about the tilt axis. Because of the advantageous operation, such combinations of slip clutch, also with hand-operated mechanical adjusting gear units, are now in demand (Deumlich, xe2x80x9cInstrumentenkunde der Vermessungstechnik [Instrumentation in Surveying Technology]xe2x80x9d, Verlag der Technik Berlin 1974, pages 87 and 88).
In order to achieve the necessary sensitivity, the worm is arranged following a screw in a second stage which accordingly forms a coarse-fine adjustment gear unit. A system of this kind is shown, for example, in U.S. Pat. No. 5,689,892 for the adjusting movement of the telescope of a theodolite. This system has the disadvantage that the two gear unit stages are arranged one behind the other and slackness occurs in the bearings, causing a disadvantageous backlash width.
Another patent, U.S. Pat. No. 5,475,930, is known from the complex of adjusting gear units for tacheometers and theodolites. This is a motor control system with a gear unit which uses a toothed belt for transmitting movement between two parallel axes.
It is the primary object of the invention to provide a device for horizontal and vertical adjustments of elements and subassemblies in geodetic devices which is particularly simple in technical respects and which reliably enables a rotation of the alidade about the standing axis and the rotation of the telescope about the tilt axis in an ergonomically favorable manner proceeding from a location with great accuracy and sensitivity. At the same time, however, a quick coarse sighting adjustment is to be realized without having to loosen a clamp or close it again before precise sighting adjustment as is known in the prior art.
This object is met according to the invention a device for horizontal and vertical adjustment in geodetic devices comprises a device for horizontal and vertical adjustment in geodetic devices comprises within its housing, a horizontal adjusting system comprising a first fine adjustment drive for rotation of the device about a vertical standing axis and a vertical adjusting system comprising a second fine adjustment drive for the movement of a telescope which is mounted in the support of the device so as to be swivelable about a horizontal tilt axis. A coaxial drive, known per se, is arranged at the support of the device and has two coaxially mounted shafts, each having a rotating knob, for initiating the rotation and/or movement of the respective parts and subassemblies. Each of the two fine adjustment gear units comprises a worm and a worm gear with a friction clutch and can be actuated jointly from a location for generating movement in two movement directions running vertical to one another or at an angle to one another. These fine adjustment gear units are arranged in two planes situated at different heights in the housing of the device, wherein the worm of one of these two fine adjustment gear units lies in the plane of the coaxial drive and each worm gear of these two fine adjustment gear units is connected, via a friction clutch, with the part or subassembly to be moved or rotated. The fine adjustment gear unit whose worm does not lie in the plane of the coaxial drive is in an operative connection, via a quarter-turn belt drive, with one of the shafts of the coaxial drive.
With respect to the belt drive, it is advantageous when a flat belt or toothed belt is provided which connects a first belt pulley fixedly arranged on one of the two shafts of the coaxial drive with a second belt pulley which is arranged on the shaft carrying the worm of one of the two fine adjustment gear units.
For this purpose, a first shaft of the coaxial drive is connected with the worm of the fine adjustment gear unit causing the rotation about the standing axis. A second shaft of the coaxial drive which is mounted in bearings on the first shaft so as to be rotatable relative to it carries the first belt pulley. The second belt pulley is fixedly arranged on a shaft carrying the worm of the fine adjustment gear unit causing the rotation of the telescope about the tilt axis. A structurally simple connection realizing the movement transmission between the belt pulleys results when the first and the second belt pulley are in an operative connection by means of a half-cross or quarter-turn flat belt or toothed belt. A movement transmission which is free of slip can be realized in particular through the toothed belt. It is advantageous when the first belt pulley is arranged on the second shaft of the coaxial drive.
In order to achieve a force transmission and movement transmission in both directions between the worms and the associated worm gears so as to be free from slack, it is advantageous when the worms are pressed against the respective worm gear in such a way by springs or spring-mounted elements arranged in the respective bearing block that the teeth mesh with one another without play and so as to be free from backlash.
The second shaft of the coaxial drive is advantageously constructed as a hollow shaft in which the first shaft of the coaxial drive is arranged so as to be mounted in rolling bearings, so that a particularly favorable space-saving construction results.
It is further advantageous when the friction clutch or slip clutch connecting the worm gears with the associated part or subsassembly to be moved is adjustable with respect to its friction torque. This can be carried out in a known manner by changing the force pressing the friction disks together.
In order to achieve a slip-free, angularly conforming movement transmission between the parts and subassemblies, a slip-free, angularly conforming coupling, advantageously a mechanical coupling, compensating for axial offset is provided between the worm of the horizontal adjusting system and the shaft of the coaxial drive driving this worm.
For example, a coupling in the form of a flex joint, a spring shaft, a web coupling or toothed coupling or a flex rod can advantageously be provided between the worm of the horizontal adjusting system and its axially arranged drive shaft.
The invention will be explained more fully in the following with reference to an embodiment example.